Apparatus for stretching dough

ABSTRACT

An apparatus is disclosed for stretching and thinning dough. This apparatus consists of a plurality of conveyors 2,3, which are disposed in series so that the traveling speed of the downstream conveyor 3 is higher than that of the upstream conveyor 2, a roller 5 that reciprocates over a given distance 1 2  transverse to the traveling direction of the dough, while reciprocating over a given distance 1 1  in the traveling direction, and a roller 4 that reciprocates over a given distance 1 1  in the traveling direction in synchronism with the transverse roller. The number of reciprocating strokes and the speed of both rollers are regulated to obtain a sheet of high quality dough with a uniform texture.

This application is a division of application Ser. No. 07/761,539, filedSep. 17, 1991 now U.S. Pat. No. 5,178,891.

FIELD OF THE INVENTION

This invention relates to the stretching of bread or cake dough. Moreparticularly, it relates to a method and apparatus whereby dough canalways be stretched and formed in a condition of uniform quality withoutits inner texture being destroyed.

PRIOR ART

A prior art apparatus has been disclosed in U.S. Pat. No. 4,692,110,owned by the assignee of the present application. In it a plurality ofconveyors that are driven at different speeds are arranged in series,and rollers are disposed thereabove to freely rotate and to reciprocatein the traveling direction of the conveyors, so that the dough placedthereon is stretched to produce a dough sheet of a uniform thickness.

This prior art technique is effective in stretching and thinning doughwhile it passes between the conveyors and rollers and is beingcompressed by means of the rollers. However, if flour dough isstretched, it has only a limited effect; namely, the stretching effectis limited to the traveling direction of the conveyor.

This is because the protein of the dough stretched in that directionhardens as it is stretched, thereby substantially preventing anystretching in other directions.

SUMMARY OF THE INVENTION

This invention aims to enhance the stretching effect by simultaneouslystretching the dough in a direction transverse to the travelingdirection of the conveyor.

It is an object of this invention to provide an effective method ofstretching dough into a thin sheet of a uniform thickness.

It is another object of this invention to provide a method forsimultaneously stretching dough in the longitudinal and lateraldirections.

It is a further object of this invention to provide an apparatus havinga roller that reciprocates in the transverse and longitudinal directionsso that the dough can be stretched in more than one direction.

In one aspect of this invention, a method of stretching dough isprovided whereby the method consists of reciprocating a roller in boththe transverse and longitudinal directions such that the rollerstretches the dough being conveyed on a conveyor in more than onedirection, to obtain an improved stretching effect.

In another aspect of this invention an apparatus for stretching dough isprovided wherein a first roller, with its axis aligned parallel to thetraveling direction of a conveyor, is such that it reciprocates over agiven distance in a direction lateral to the traveling direction of aconveyor while reciprocating over a given distance in the travelingdirection, and wherein a second roller disposed downstream of the firstroller, with its axis positioned at a right angle to the travelingdirection, is arranged to reciprocate over a given distance insynchronism with the first roller. The rollers are simultaneouslyreciprocated over a given distance in the traveling direction and over agiven distance transverse direction, to stretch the dough. The speed ofthe movement of each of these rollers in each direction can be adjusted,thereby the locus of the rolling of the rollers can be freely changed.

The selection of the locus of the rolling movements enables theapparatus to stretch the dough in various directions so that a sheet ofdough of a uniform thickness and of a uniform quality is formed in ahighly effective manner.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a side view of a roller assembly of an embodiment of thisinvention.

FIG. 2 is a schematic top view of the roller assembly of the embodiment.

FIG. 3 is a partial perspective view of the apparatus of the embodiment.

FIG. 4 is a partial top view of a first roller of the embodiment.

FIGS. 5, 6, and 7 are side views of roller assemblies used inconventional stretchers.

FIG. 8 is a schematic diagram illustrating the loci of rollers used inthis invention.

DESCRIPTION OF THE PREFERRED EMBODIMENT

In FIG. 1 an upstream conveyor 2 and a downstream conveyor 3 aredisposed in series. The upstream conveyor 2 receives from an upstreamsource an indeterminate form of a continuous mass of dough 1. Theupstream and downstream conveyors are independently driven by theirrespective motors (not shown), so that the downstream conveyor 3 isdriven at a higher speed than the upstream conveyor 2.

Three rollers 4, 4' and 5 are supported by a roller frame 6, which is inturn slidably supported by the frame for the apparatus (not shown), sothat the frame 6 can reciprocate over a given distance 1₁ in thetraveling direction of the conveyor.

The rollers 4, 4' are disposed above the conveyors, and are spaced apartfrom the downstream conveyor 3 by a given distance D, so that theybridge the conveyors, and their axes are perpendicular to the travelingdirection of the dough on the conveyors. The reciprocation of the frame6 causes the rollers 4, 4' to reciprocate over a given distance 1₁(FIG. 1) in the traveling direction while rolling.

A roller 5 is disposed upstream of the rollers 4, 4'. The gap betweenthe conveyor and the roller 5 is the same as or a little larger than thegap D between the conveyor 3 and the roller 4.

The roller 5 is oriented at right angles with the rollers 4, 4', itsaxis being aligned with the traveling direction of the dough on theconveyors and as shown in FIGS. 2 and 4. It reciprocates over a givendistance 1₂.

The roller 4 is mounted on a shaft 41. A sprocket 42 is mounted on theshaft 41 and fixed thereto.

The sprocket 42 meshes with a chain 71 that is driven by avariable-speed motor 7 so that it goes around two sprockets that arepositioned spaced apart from each other by a preset distance. The chainmoves parallel to the conveyors.

The shaft 41 is pivotally mounted on one end of a crank rod 81. Thecrank rod 81 is driven by another variable-speed motor 8 so that theshaft 41 is simultaneously rolled and reciprocated through the movementof the sprocket 42 on the chain 71 and caused by the reciprocating crankmotion of the crank rod 81.

Hence, when the crank rod 81 is operated, the roller 4 can be rolled andreciprocated by means of the operation of the sprocket 42, which isreciprocated by the motor 8 through the crank rod 81 on the chain 71.

The rollers 4 and 4' are connected via a belt 43 so that the movement ofthe roller 4 is transmitted to the other roller 4', and so that thelatter can roll and proceed back and forth in the same manner as theroller 4. By means of the transmission ratio of the belt 43, thediameters of pulleys attached to the rollers are adjustable so that theperipheral speed of the upstream roller 4' is kept lower than that ofthe downstream roller 4.

In this embodiment the variable-speed motor 7 is adjusted such that thespeed of the movement of the chain 71 is the same as the speed of thedownstream conveyor 3. The roller 4 is reciprocated so that it movesbetween the upstream and downstream conveyors 2, 3. By adjusting thevariable motor 7 and the transmission belt 43, the peripheral speed ofthe roller 4' is forcedly kept higher than the speed of the upstreamconveyor 2 and slower than the speed of progress at which it rolls overthe downstream conveyor 3 without causing substantially any frictionwith the dough.

The shaft 51, on which the roller 5 is mounted, is supported at bothends by the arms of a U-shaped slider 52. A pinion 53 is mounted on oneend of the shaft 51. A small-diameter pinion 54 is mounted on a wall ofthe slider 52 so as to mesh with the pinion 54.

The pinion 54 engages a rack 55, which is fixed on the frame 6 in thedirection transverse to the conveyor.

The slider 52 is slidably mounted on two rods 56 that span the frame 6in the direction transverse to the axis of the shaft 51. The roller 5 isdriven by an independent power device, such as a rotary actuator or areversible motor (not shown), which is mounted on the shaft 51 to rollthe roller 5. The roller 5 is made to reciprocate by means of thepinions 53, 54, and the rack 55.

The moving speed of the roller 5 can be changed by a regulator 57 (FIG.3).

In a first embodiment, as shown in FIG. 2, the rolling locus of theroller 5 is such that when the roller makes one reciprocating stroke inthe direction of the movement of the conveyors over the distance 1₁, itmakes one-half of a reciprocating stroke in the transverse directionover the distance 1₂, so that the dough 1 being carried on the conveyoris stretched by the roller moving along the locus formed by the combinedlengthwise and sidewise movements of the roller.

FIG. 8 shows nine combined loci that are formed. While the roller makesno stroke, or makes one or two reciprocating strokes in the lengthwisedirection over the distance 1₁, it makes a half, one and a half, or twoand a half reciprocating strokes in the transverse direction over thedistance 1₂. The loci thus obtained are as shown in FIG. 8. If theroller makes no stroke in the lengthwise direction while it makes a halfstroke in the transverse direction, the upper left locus will beproduced. If the strokes in the transverse direction are increased to1.5, the upper middle locus will be given. If the transverse strokes areincreased to 2.5, the upper right locus will be given. If the rollermakes one stroke in the lengthwise direction over the distance 1₁, whileit makes half a stroke transverse, the locus will be as shown in thesecond block on the lefthand column.

In the embodiments of this invention the roller affects the surface ofthe dough in various directions, so that dough having an inner textureof a uniform quality, in any direction, can be obtained.

Further, the rollers 4, 4' of this invention stretch dough in thedownstream and upstream directions in such a manner that the thicknessof the dough can be adjusted.

Experiments to evaluate the effects of this invention for bread doughshowed that when a dough sheet 20 mm thick was stretched by theconventional rollers shown in FIGS. 5, 6, and 7, each under similarconditions, the resulting sheets of dough were 10, 5, and 5 mm thick,respectively.

In contrast, under the same experimental conditions the apparatus ofthis invention achieved a sheet of dough 2 mm thick. Namely, thereduction ratio of the embodiment of this invention was 1:10, while thatof the conventional rollers was 1:4 or 1:2. This proves the remarkableadvantage of this invention.

THE EFFECTS OF THE INVENTION

As is explained above, by providing rollers that reciprocate in both thedirection of travel of dough and the transverse direction, the methodand apparatus of this invention can stretch dough in various directionsso that a sheet of a high quality dough with a uniform texture andthickness can be obtained from a continuous mass of dough conveyed in anindeterminate shape.

We claim:
 1. An apparatus for stretching dough comprising:a plurality ofconveyors disposed in series so that a first conveying speed of adownstream conveyor is higher than a second conveying speed of anupstream conveyor, the dough being conveyed from the upstream conveyorto the downstream conveyor in a traveling direction; and a rollerrotatably disposed on an axis and disposed adjacent the plurality ofconveyors, the axis being aligned parallel to the traveling direction ofthe plurality of conveyors wherein the roller reciprocates over a firstgiven distance in a direction lateral to the traveling direction whilereciprocating over a second given distance in the traveling direction.2. An apparatus for stretching dough comprising:a plurality of conveyorsdisposed in series so that a first conveying speed of a downstreamconveyor is higher than a second conveying speed of an upstreamconveyor, the dough being conveyed from the upstream conveyor to thedownstream conveyor in a traveling direction, a first roller rotatablydisposed on a first axis and disposed adjacent the plurality ofconveyors, the first axis aligned parallel to the traveling direction ofthe plurality of conveyors wherein the first roller reciprocates over afirst given distance in a direction lateral to the traveling directionwhile reciprocating over a second given distance in the travelingdirection, and a second roller disposed downstream of the first roller,the second roller being rotatably disposed on a second axis positionedat right angles to the traveling direction, the second roller beingarranged to reciprocate over a third given distance in a directionparallel to the travel direction in synchronism with the first roller.3. The apparatus of claim 2 in which the first and the second rollersare rotatably fixed to a frame positioned above the plurality ofconveyors.